PIPE questions for Linux 2.4 setup

PIPE questions for Linux 2.4 setup

[Ad van den Broek]

Dear C/Linux friends,

We wanted to increase PIPE_SIZE (from 4K to 8K on linux 2.4 on an AMD
LX800 system).
The result is a segmentation error as soon as Read() is reading more
data than 4K
from the pipe.
So pipe data seems to be damaged.
If we change PIPE_SIZE back tot 4K everything is running fine.
Question-1: Any suggestion to prevent this segmentation error ?

* PIPE_SIZE
If you look in the linux kernel code for PIPE_SIZE
("include/linux/pipe_fs_i.h") you find:
#define PIPE_SIZE PAGE_SIZE
I don't know if #define PIPE_SIZE PAGE_SIZE is necessary or just a
simple shortcut.
Question-2: Is it OK if PIPE_SIZE > PAGE_SIZE ?

* PAGE_SIZE
Question-3: Is it OK to increase Page_size on linux 2.4 on AMD LX800 system ?
Which aspects are limiting the user to config the PAGE_SIZE ?

-- 

With best regards,
Ad van den Broek

Re: PIPE questions for Linux 2.4 setup

[Glynn Clements]

Ad van den Broek wrote:

> Dear C/Linux friends,
> 
> We wanted to increase PIPE_SIZE (from 4K to 8K on linux 2.4 on an AMD
> LX800 system).
> The result is a segmentation error as soon as Read() is reading more
> data than 4K
> from the pipe.
> So pipe data seems to be damaged.
> If we change PIPE_SIZE back tot 4K everything is running fine.
> Question-1: Any suggestion to prevent this segmentation error ?
> 
> * PIPE_SIZE
> If you look in the linux kernel code for PIPE_SIZE
> ("include/linux/pipe_fs_i.h") you find:
> #define PIPE_SIZE PAGE_SIZE
> I don't know if #define PIPE_SIZE PAGE_SIZE is necessary or just a
> simple shortcut.
> Question-2: Is it OK if PIPE_SIZE > PAGE_SIZE ?
> 
> * PAGE_SIZE
> Question-3: Is it OK to increase Page_size on linux 2.4 on AMD LX800 system ?
> Which aspects are limiting the user to config the PAGE_SIZE ?

The page size is hardcoded in silicon; you can't change it in
software.

And the kernel itself no longer refers to PIPE_SIZE (it did in earlier
2.6 versions), so there's not much point in changing it.

-- 
Glynn Clements <glynn@gclements.plus.com>